Front Page

May 5th, 2014

Thinking Clearly – Sifting Through The Noise

Logic – For the love of it was developed to provide a resource for those who wish to explore the realm of Logical fallacies. Some of the content is original and some garnered from the enterprise of others. It is, and will continue to be, a work in progress.

“Logic tells us what makes sense, passion often convinces us to ignore it.“

-- Jeffrey Slee

What Are Fallacies

Fallacies are misconceptions or mistakes in reasoning — any “argument” in which the premises given for the conclusion do not provide the needed degree of support.

There are, of course, other types of mistake than mistakes in reasoning but logical fallacies often exploit emotional triggers in the listener or interlocutor. For example, an argument may appeal to constructs such as nationalism, religion, family or may exploit an intellectual weakness of the listener. Fallacious arguments may also take advantage of social relationships between people. For example, citing an important individual’s support for a view on any other subject than the one discussed in order to encourage listeners to either agree or disagree with that person.

Considered by themselves, fallacies can often seem obviously bad. However, arguments are often structured using rhetorical patterns that obscure the logical argument – deliberately or not – making fallacies difficult to diagnose. Also, the component parts of the fallacy may be spread over a large period of time.

Formal and Informal Fallacies

Informal fallacies apply to inductive arguments which are arguments that, while not violating propositional calculus rules, are invalid because of the content of their argument. The types of mistakes in reasoning that arise from the mishandling of the content of the propositions constituting the argument. Whereas, formal fallacies apply to deductive arguments and follow a pattern of reasoning which is always wrong. This is due to a flaw in the logical structure of the argument which renders the argument invalid.

Forming The Argument

1. The arguments begin with introductory statements. It is the initial evidence to support an argument or the premise. The premise usually contains two or more statements.

2. All the introductory evidence of the premise should hint, imply, or lead to a certain conclusion. The process of getting a conclusion from the premise is called inference.

3. Finally, the premise and inference together should ultimately support or prove the argument or the conclusion.

Taxonomy of Logical Fallacies

To better understand these fallacies it is useful to group and classify them within a hierarchical structure, but there is no one correct taxonomy of fallacies. Aristotle, the first logician to name fallacies, classified them into 13 types (Sophistici Elenchi ) divided between two classes:

• Linguistic(in dictione): Those which depend on language.
• Non-linguistic(extra dictionem): Those which do not depend on language.

Since then, logicians proposed fallacy lists of different length, in different sets, and with different names. Therefore any grouping of fallacies is bound to be arbitrary in some degree. Subsequent, logicians have usually extended Aristotle’s classification by subdividing the second ( non-linguistic category) into many more. Traditionally, most such classifications have remained non-hierarchical , with all fallacies on the same level, but these classification reveal the complexity of the logical relations between different fallacies and the hierarchy that exists.